In certain network connections, such as connections made over the Hypertext Transfer Protocol (“HTTP”), it can be desired to maintain a persistent connection between the client and the web-server in order to reduce the overhead needed to reestablish the connection.
However, Network Address Translation (“NAT”) gateways and other equipment that lie along the connection pathway may terminate the connection in the event that the connection goes idle beyond a predefined period of time.
In order to prevent NAT gateway from terminating the connection, it is known to periodically send “keep-alive” packets from the client to the web-server. Such keep-alive packets do not actually include any transactional information and have no effect on the state of the data between the client and the web-server, and are merely used to prevent the NAT gateway from terminating the connection. It is typical to aggressively send keep-alive packets, without any regard to the actual parameters used by the NAT gateway, and thereby implement a universal strategy to keep the connection open.
However, these prior art methods of maintaining persistent connections are ideally suited to channels where bandwidth is not constrained. Thus, in bandwidth constrained mediums, such as wireless network channels, this strategy is wasteful of precious bandwidth. This prior art method is also undesirable in battery operated devices, where aggressive delivery of keep-alive packets could quickly drain the battery.